Proteomic Analysis of the Periodontal Ligament During Orthodontic Movement: A Study in Rats.

The periodontal ligament (PDL) is a dynamic connective tissue that absorbs and transmits mechanical forces, playing a critical role during orthodontic tooth movement (OTM). This study aimed to characterize the proteomic profile of rat PDLs subjected to OTM. Ten Holtzman rats were allocated into Control and OTM groups. After 15 days of force application, hemimaxillae were harvested, and PDL tissues from the first maxillary molars were isolated via laser capture microdissection. Protein extracts were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), followed by quantitative and enrichment analyses. Immunohistochemistry was performed to validate selected proteins. The full proteomic datasets supporting these findings are available in the PRIDE repository under the identifiers PXD055817 and PXD033647. A total of 1121 proteins were identified; 101 were exclusive to the OTM group, 324 to the control, and 696 shared. Among the 335 proteins with differential abundance, 334 were downregulated and one (Prelp) was upregulated in the OTM group. Enrichment analysis revealed that differentially abundant proteins were associated with molecular functions such as protein binding, and cellular components including extracellular exosomes, focal adhesions, and the extracellular matrix. Immunohistochemical analysis confirmed the presence of Prelp, Rbm3, and Cirbp in PDL tissues. These findings demonstrate that OTM significantly alters the proteomic landscape of the PDL and identify key proteins potentially involved in periodontal remodeling.